January to March
These are the main summer rainy season months for this part of Africa, and some of the parks become inaccessible like Mana Pools and for those with access the road network might be quite limited like Gonarezhou National Park.
It is however an excellent time to see the parks when animals, birds and plants are at their best and parks like Hwange on the Kalahari sands are fantastic. I really enjoy this time of year and I do recommend doing it as a complete contrast to the usual dry conditions that people see.
Sept - Oct
These months are when the temperatures start to climb and the wildlife concentrates at the last available feeding and watering sites. September is probably the best of these months from a temperature perspective as October can be really hot during the day going towards the 40 degrees Celsius mark in the low altitude parks like Mana Pools and Gonarezhou, but it does cool off at night time. At this time many species of tree start to flower and migratory birds start arriving. For some, these are the best months to be on safari to see the drama before the rains or the spectacle of nature when the first rains arrive.